The elevation and plan of one of the celebrated French racing-machines, the Vallée car, is shown in [Fig. 12]. The motor of this machine is of sixteen horse-power capacity, has four cylinders, and is connected so as to impart motion to the hind axle by means of a single wide belt, which is marked G in both the line drawings. The driving-pulley on the motor shaft is located at H, and the axle pulley at H’. Within the latter there is a train of gears for reversing the direction of rotation of the axle, and also for obtaining the differential velocities of the two driving wheels. There is no mechanism for variable speed, this being obtained wholly by changes in the velocity of the motor. The motor speed can be made to vary through a wide range by using four cylinders, with which it is possible to reduce the velocity so low that it would be likely to bring the machine to a standstill if provided with one, or even two, cylinders. The change in the motor velocity is obtained in part by the action of a governor located in a chamber at A, and in part by the action of the electric ignition device which is arranged so that the time when the spark is produced can be varied. The rear axle is so held that it can be moved through a short distance, horizontally, by manipulating the lever D, and in this way the belt G can be made tight or loose, thus affording another means for varying the speed. A brake is provided which presses against the inner side of the axle pulley, H. This brake is used ordinarily, but in the case of an emergency another brake can be operated which presses against the outside of the wheel in the space between the two sides of the belt. It is claimed for this vehicle that by the elimination of mechanical speed-changing devices, a great deal of weight is saved, and that this is more than enough to compensate for the extra weight of the motor, arising from the use of four cylinders. In most gasoline carriages it is necessary to provide a slow-speed gear for hill-climbing, as the motor cannot put forth a sufficient effort to ascend a steep grade at the normal velocity. With this racing-machine such a gear is not required owing to the enormous power of the motor.
Fig. 12. Elevation and Plan of Vallee Car.
There are quite a number of gasoline automobiles manufactured in this country, and, as in the case of the steam and the electric carriages, they compare most favorably with the best European products, in so far as the artistic effect is concerned. That such is the case can be realized at once by an examination of [Figs. 13] and [14]. We regret our inability to illustrate the mechanism of these vehicles, but the truth is, that the manufacturers appear to be unwilling to make public the details of their designs. In the phaeton shown in [Fig. 13], a single-cylinder motor is used, and it is so arranged that it can run at different velocities, so that no variable speed mechanism is required, except a single train of gears, which is thrown into action when running uphill. The motor itself can be run at any velocity from 200 to 800 revolutions per minute, thus giving a speed variation of four to one. A carriage of this make competed in the last international automobile race from Paris to Lyons, France, and although it failed to come in first, it made a remarkable showing, which might have been considerably improved if it had not been for an accident which compelled it to retire from the contest.
Fig. 13. Winton Phaeton.
Fig. 14. Oakman Vehicle.
The vehicle shown in [Fig. 14] is of small size and light construction, although amply strong for the purpose for which it is intended. The power of the motor, which is located under the seat, is transmitted through friction wheels. In looking at the illustration it will be noticed that the hind wheels have a circular rim attached to the inner side, and of a diameter somewhat smaller than the wheel itself. Two small friction wheels are placed so that either one may be pressed against the inner surface of this rim. The shape of the rim, as well as that of the small wheels, is such that they hug each other firmly, so that the rim is carried around in a direction which corresponds with the direction of rotation of the friction wheel. In operating the carriage the motor is set in motion, and then one or the other of the two friction wheels is pressed against the rim on the driving wheel, according to whether it is desired to run forward or backward. While this arrangement might not operate with entire success if applied to a heavy vehicle, it appears to be all that could be desired for a light carriage.
Three-wheel vehicles have been used, but there is a difference of opinion as to their value, as the construction has disadvantages as well as advantages. It is evident that such a vehicle can be steered with greater ease than one running on four wheels, but on country roads, where the wagon wheels roll down a smooth surface, and leave the space between in a rough condition, it is equally evident that the third wheel, in passing over this uneven surface, would jolt the vehicle to a considerable extent. On a smooth pavement the three-wheel vehicle will run fully as well as the four-wheel; but, on the other hand, on such a pavement the latter can be steered with as little effort as the former, so that the question of superiority of design is one that probably depends upon individual taste.